The Robert H. Lurie Comprehensive Cancer Center Flow Cytometry Core Facility provides comprehensive flow cytometry and cell sorting services. The Flow Cytometry Core Facility serves investigators of the Cancer Center, Northwestern University Medical School, Northwestern University and other affiliated institutions by providing access to routine flow cytometry assays such as immunophenotyping and DNA analysis. However, the major mission of the facility is to provide the guidance, technical assistance, and equipment for investigators to utilize more complex multi-parametric, multi-laser measurements as well as cell sorting in their research regardless of their level of cytometry expertise. The Core Facility has an international reputation and extensive experience in developing and implementing complex multi-parametric assays with particular expertise in intracellular liable antigen detection such as phosphorylated protein epitopes. This level of expertise along with the equipment housed within the Core Facility permits implementation of most flow cytometry assays that have been published. Services provided by the facility extend from consultation on experimental design, sample preparation and data analysis to instrument operation and set-up for cell sorting and multi-laser operation. In addition, the Core Facility has an active program of assay development guided by the interests/needs of the investigators. Reflective of the facility's commitment to flow cytometry education/ training of the next generation of researchers, user training for operation of not only less complex analysis instruments but also the more complex analyzer and sorting instruments is offered. Thus, the Flow Cytometry Core Facility serves as a focus for individuals interested in cellular based measurements and cellular heterogeneity in disease providing critical support for cancer related research within the institution. The Chicago campus facility includes three cell sorters; a 5 laser/15 parameter MoFlo high speed cell sorter (Beckman-Coulter. BC) along with two new Becton-Dickinson (BD) FACSAria 111 cell sorters, a 4 laser/13 parameter instrument and a 5 laser/17 parameter instrument housed in a Bio-containment hood and negative pressure room; and a 3 laser, 10 parameter FACSAria II (BD) on the Evanston campus. The Chicago campus facility also has three benchtop flow cytometry analyzers; a 6 laser/18 parameter FORTESSA (BD), a 3 laser/11 parameter Cyan (BC) and a single laser/six parameter XL (BC) with the Evanston facility having a 4 laser/13 parameter LSRII (BD). In addition, the Chicago facility has a ViCell cell counter/viability instrument (BC). The facility has multiple offline analysis workstations providing the components for post acquisition data analysis and graphics generation. The Core Facility is now heavily utilized by a wide number of investigators (148), approximately 62% of which are Cancer Center members who account for approximately 74% of core utilization